Abstract

We consider the image interpolation problem where given an image
vm,n
with uniformly-sampled pixels vm,n and point spread function h, the
goal is to find function u(x,y) satisfying vm,n = (h*u)(m,n)
for all m,n in Z.

This article improves upon the IPOL article Image Interpolation
with Contour Stencils. In the previous work, contour stencils are used
to estimate the image contours locally as short line segments. This
article begins with a continuous formulation of total variation
integrated over a collection of curves and defines contour stencils as
a consistent discretization. This discretization is more reliable than
the previous approach and can effectively distinguish contours that
are locally shaped like lines, curves, corners, and circles. These
improved contour stencils sense more of the geometry in the image.

Interpolation is performed using an extension of the method described
in the previous article. Using the improved contour stencils, there is
an increase in image quality while maintaining similar computational
efficiency.